EP3460305A1

EP3460305A1 - Restraining clamp ring for joining two pipes and pipes to fittings

Info

Publication number: EP3460305A1
Application number: EP17202505.8A
Authority: EP
Inventors: Abhijit Sengupta; Sanjib Das
Original assignee: Electrosteel Casting Ltd
Current assignee: Electrosteel Casting Ltd
Priority date: 2017-09-23
Filing date: 2017-11-20
Publication date: 2019-03-27
Anticipated expiration: 2037-11-20
Also published as: EP3460305B1; ES2841529T3

Abstract

The present invention relates to a pipe joint assembly adapted for use in high pressure pipe fittings comprising of a socket end (7) of one pipe which has a taper end (8) of another pipe is inserted, wherein the socket has a cavity (7A) with at least two openings (7B); and a restraining clamp ring (1) for holding the taper (8) end inside the socket by a "V" shaped recess (2A) having two ring type clamping halves (1A), each having two lever arms (1C) extending along the length of the pipe.

Description

FIELD OF INVENTION

The present invention relates to a pipe joint assembly adapted including a clamp device for use in pipe fittings. More particularly, the present invention relates to a Restraining Clamp Ring for jointing two pipes and pipes to fittings to avoid axial separation of pipes or fittings, during pressurization of the pipe line.

BACKGROUND ART

One well known form of pipe joint, for example, comprises a bell end provided on one pipe, an inter-fitting spigot end on an attached pipe, and a sealing gasket interposed between the bell and spigot ends. Numerous locking arrangements have been proposed for use in such joints to prevent axial movement of the spigot end relative to the bell end. Thus, for example, one such locking arrangement employs a split ring located inside of the bell end and which can be adjusted radially by a ring adjustment mechanism between a relaxed condition allowing for axial movement of the respective pipe ends and a tightened position in which the ring engages a circumferential bead or the like on one of the pipe ends to preclude relative axial movement there between in a direction separating the pipes.
In some devices, the adjustment mechanism for the snap ring comprises transverse pieces which extend axially from the respective ends of the split snap ring out of the mouth of the bell end, radial lugs on the outer ends of the transverse pieces, and a threaded stud connecting the lugs whereby radial adjustment of the segmented ring within the bell end as between the relaxed and tightened conditions is effected externally of the bell end by rotating the threaded stud nuts in the appropriate direction.
In the prior art, a French application FR2376985 (A1 ) discloses a socket or sleeve pipe coupling having an outer clamp ring with internal cones to successively deform outer coupling member. The pipe coupling is affected by clamp rings with conical inner surface being secured over the socket end or the outer sleeve. This produces a sealed joint between the pipe and sleeve by inward deformation. Each clamp ring has a first conical inner portion followed by a cylindrical portion and a second conical portion. The diameter of the cylindrical portion is equals to the small diameter of the first and the large diameter of the second conical portion. The outer diameter of the sleeve before fixing the ring approximately equals the large diameter of the first portion.
In another prior art, a European application EP2336624 (A2 ) discloses a clamp ring for use in a socket joint. The disclosed fitting has a socket for forming an inward projecting socket edge at a socket opening, and a clamping ring with ring segment shape clamping ring parts. Ring sections of the socket engage in a socket inner chamber in a form-fit manner. The ring sections are pre-stressed with each other at a pipe at clamping ring bars by clamping elements. The clamping ring parts at a side of the clamping elements are formed with support elements, where the side is turned away from the socket. The support elements are supported at an external surface of the pipe.
In yet another prior art, a European application EP2940362 (A1 ) discloses a spigot-and-socket pipe joint. A stopper ring of the joint has a split structure comprising a plurality of stoppers. Two or more fixing holes are provided in the face of the outer diameter of each stopper for installing an elastic support. During installation, the stoppers are first installed in a stopper chamber one by one to form a whole and finally a spigot is installed into a socket. During the installation, a spigot projection can push the stopper to move backwards and compress the elastic support on the stopper ring when passing through the stopper ring, and the spigot projection would pull the spigot back after passing through the stopper ring, so that the stopper presses against the outer surface of the spigot by the elastic support. The spigot-and-socket pipe joint in the invention has simple structure, convenience in installation and disassembly, strong anti-slip capability and wide application.
While pipe joints of the general type referred to above are in extensive use and are generally regarded as being satisfactory in performance, the present invention seeks to improve the design thereof in certain respects, more particularly in regard to the locking ring structure, so as to provide, inter alia, improved joint performance and characteristics.

SUMMARY OF INVENTION

It is a principal object of the invention to provide an improved form of restrained pipe joint of the general type referred to, particularly for use in pipes, which has a clamp assembly structure affording greater flexibility, and accommodating a higher degree of misalignment as between the respective pipe ends than in known joints, while maintaining an adequate seal between the pipe ends and adequate axial restraint thereof.
It is another object of the present invention to propose a clamp assembly of the aforementioned kind which can be used without significant extra expenditure also for sleeve joints and still provides a reliable connection. Moreover, a simple sleeve joint using such a clamp assembly is being provided.
Therefore such as herein described, there is provided a restraining clamp ring (1) adapted for use with pipe joint assembly and / or pipe fittings wherein the pipe joint assembly includes overlapping of a socket end (7) of one pipe and a taper end (8) of another pipe, wherein the socket has a cavity (7A) with at least two openings (7B); and wherein the taper (8) end of the pipe is held inside the socket by a "V" shaped recess (2A) having two ring type clamping halves (1A), each having two lever arms (1C) extending along the length of the pipe.
In accordance with the present invention, the said restrained joint is achieved by a restraining clamp ring assembly including two ring type clamping halves each having two lever arms extending along the length of the pipe. Also, the piping system includes a socket end of one pipe wherein the taper end of another pipe is inserted. The said socket has a cavity with at least two openings and the said clamping assembly is configured for holding the taper end inside the socket by a "V" shaped recess.
As per another aspect of the present invention the clamping halves possess two rotating members when position in proper place and bolts of the lever arms are tightened ensures that movement of the free ends of the arms are restricted and entire movements is transmitted to the rings ensuring proper biting of the teeth on the spigot.
As per yet another aspect of the present invention, there is provided position pins, configured for restricting the movement of arms and the said movement are transmitted to the open side of the arms as there is a presence of resisting force and transmit the tightening torque to biting force at recesses.
As per yet another aspect of the present invention, the said position pins ensure proper alignment of the halves and do not allow any axial movement of the halves, irrespective of dimensional tolerances of the mating parts, proper biting of V shaped recess in the spigot metallic wall.
As per yet another aspect of the present invention, the said clamping halves (1), so connected and configured, are inserted in to the socket end restraining chamber and retracted to the inner periphery of socket restraining chamber to create maximum internal diameter to allow insertion of spigot end easily through it. The spigot end of pipe is then pushed in to the socket, up to the required insertion length.
Such a configuration of the clamping assembly has been found to be particularly advantageous, in particular from the point of view of the clamping action and the handling.
Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawing.
It is to be understood that the features mentioned above and those which are still to be explained below can be used not only in the particular combination indicated but also in other combinations or in a single setting without departing from the scope of the present invention. The invention and its embodiments will be explained in the following by means of a preferred embodiment illustrated in the drawing.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Fig.1 is a side view and magnified view of an embodiment of a pipe connection with restraining clamp ring assembly for jointing two pipes and pipes to fittings in accordance with the present invention; and
Fig. 2 is an exploded view of the clamp ring assembly according to the present invention.

DETAILED DESCRIPTION

The present invention relates to a Restraining Clamp Ring for jointing two pipes and pipes to fittings to avoid axial separation of pipes or fittings, during pressurization of the pipe line in particular reference to Fig. 1. Several restraining mechanisms to avoid axial separation of pipes or fittings, during pressurization, are available. Most of these mechanisms require factory applied weld bead at the end (spigot end) of pipes. Making weld bead at site condition is very difficult, as it requires special equipments, consumables and expertise. This invention will work without any weld bead for restrained flexible joint.
Clamp ring is designed in two halves (1). Each half (1) has a radially inward metallic projecting edge (2) with at least two sharp "V" shaped recesses (2A). Both ends of each half (1) have an extended lever arm (1B) along pipe's longitudinal axis. Lever arm (1B) has a hole (1C), parallel to pipe's horizontal diametral axis, to pass a clamping bolt (5) through it. End of lever arm (1B) has a rectangular slot (1D), parallel to pipe's horizontal diametral axis, to allow a pin (3) through it. External diameter of this pin (3B), at the middle of its length, is bigger than the length of the slots (W). One end of the pin (3A) is hinged at one of the lever slots (1D), in such a way, so that other end (3A)is free to rotate and can be rest on the slot (1D) of other lever arm (1B). This pin (3), thus rested at both the slots (1D), favors proper alignment of clamping halves (1), with respect to pipe axis, during tightening of clamping bolts (5) and act as a lever fulcrum (4) to transmit tightening torque to biting force at V shaped recess (2A) on the pipe's (8) external periphery.
As shown in Fig. 2, the two clamping halves (1) are initially connected, loosely, to each other, by means of two clamping bolts (5), passing through the holes (1C) provided at the end of lever arms (1B). Clamping halves (1) are loosely connected so that internal diameter comprises by these two halves (1), can be varied. Clamping halves (1), so connected, are inserted in to the socket (7) restraining chamber and retracted to the inner periphery (7A) of socket restraining chamber to create maximum internal diameter to allow insertion of spigot (8) end easily through it. Spigot end (8) of pipe is then pushed in to the socket (7), up to the required insertion length. Then the clamping bolts (5) are tightened. Before tightening, it is to make sure that the hinged pin's (3) ends are rested in lever arm slots (1D). These pins transmit the tightening torque to biting force at recesses (2A). The sharp edge of the recess bites the pipe (8) and thus does not allow it to separate during pressurization. During tightening of the clamping bolts (5), the pins (3) in between two slots of lever arms prevent tilting of the clamping halves (1) and act as a fulcrum to transmit the tightening torque to biting force at the sharp "V" shaped recesses (2A) effectively on the periphery of spigot (8) end. Thus, reliability of biting of recesses (2A) is ensured, irrespective of tolerance of components.
The said clamping rings (1) are preferably made with ductile Iron (420/5). Preferably, the tip of the recess (2A) is especially hardened to 510 BHN to ensure easy biting into the spigot end.
Although the foregoing description of the present invention has been shown and described with reference to particular embodiments and applications thereof, it has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the particular embodiments and applications disclosed. It will be apparent to those having ordinary skill in the 10 art that a number of changes, modifications, variations, or alterations to the invention as described herein may be made, none of which depart from the spirit or scope of the present invention. The particular embodiments and applications were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the 15 art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such changes, modifications, variations, and alterations should therefore be seen as being within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.

Claims

A restraining clamp ring (1) adapted for use with pipe joint assembly and / or pipe fittings wherein the pipe joint assembly includes overlapping of a socket end (7) of one pipe and a taper end (8) of another pipe, wherein the socket has a cavity (7A) with at least two openings (7B); and wherein the taper (8) end of the pipe is held inside the socket by a "V" shaped recess (2A) having two ring type clamping halves (1A), each having two lever arms (1C) extending along the length of the pipe.
The restraining clamp ring as claimed in claim 1, further includes a pair of clamping halves (1) with two rotating members when position in proper place and bolts of the lever arms are tightened ensures that movement of the free ends of the arms are restricted and entire movements is transmitted to the rings ensuring proper biting of the teeth on the spigot.
The restraining clamp ring as claimed in claim 2, wherein the said clamping half (1A) includes a radially inward metallic projecting edge (2) with at least two sharp "V" shaped recesses (2A).
The restraining clamp ring as claimed in claim 2, wherein the lever arm (1B) includes a hole (1C), parallel to pipe's horizontal diametral axis, to pass a clamping bolt (5) through it.
The restraining clamp ring as claimed in claim 4, wherein the end of lever arm (1B) includes a rectangular slot (1D), parallel to pipe's horizontal diametral axis, to allow a pin (3A, 3B) through it
The restraining clamp ring as claimed in claim 5, wherein the external diameter of the pin (3B), at the middle of its length, is bigger than the length of the slots (W).
The restraining clamp ring as claimed in claim 5, wherein one end of the pin (3A) is hinged at one of the lever slots (1D), in a way, that other end (3A) is free to rotate and rest on the slot (1D) of other lever arm (1B).
The restraining clamp ring as claimed in claim 5, wherein the said pin is rested at both the slots (1D), favors proper alignment of clamping halves (1), with respect to pipe axis, during tightening of clamping bolts (5) and act as a lever fulcrum (4) to transmit tightening torque to biting force at V shaped recess (2A) on the pipe's (8) external periphery.
The restraining clamp ring as claimed in claim 2, wherein during use, the two clamping halves (1) are initially connected, loosely, to each other, by means of two clamping bolts (5), passing through the holes (1C) provided at the end of lever arms (1B).
The restraining clamp ring as claimed in claim 1, wherein the said pins transmit the tightening torque to biting force at recesses (2A) and the sharp edge of the recess bites the pipe (8) and does not allow it to separate during pressurization.
The restraining clamp ring as claimed in claim 1, wherein the pins (3A, 3B) placed in between two slots of lever arms prevent tilting of the clamping halves(1) during tightening of the clamping bolts (5), and act as a fulcrum to transmit the tightening torque to biting force at the sharp "V" shaped recesses (2A) effectively on the periphery of spigot (8) end.
The restraining clamp ring as claimed in claim 1, wherein the clamping rings (1) are preferably made with ductile Iron (420 /5).
The restraining clamp ring as claimed in claim 8, wherein the tip of the recess (2A) is preferably hardened to 510 BHN to ensure easy biting into the spigot end.